Abstract

Background: Research suggests that individuals with autism struggle to recognise and understand the emotional expressions of others, potentially leading to communication difficulties in everyday social interactions. Typically developing adults usually perceive stronger emotion in the left hemiface (predominantly controlled by the emotional right hemisphere) when observing photographs of models. Similarly, when presenting their own poses, they tend to offer the left hemiface to convey heightened emotional states (Nicholls, Wolfgang, Clode and Lindell, 2002).
Objectives: This study investigates how individuals with autism view emotional expressions in the hemifaces of others and how they portray their own emotional expression in lateral poses. It was predicted that typically developing individuals will select the left hemiface as being more expressive when observing pictures of models, whereas participants with autism may show a reduced, or reversed, asymmetry in their hemiface selections. Moreover, typically developing participants will portray their own emotional expressions using their left cheek whereas individuals with autism may show a sporadic selection of either left or right poses.
Methods: Seventeen adolescents with ASD aged between 12 and 15 years were individually matched on chronological age and Full Scale IQ to 17 adolescents without ASD. The first task assessed the perception of emotional expressions by showing participants a series of slides, each depicting a right and left cheek pose of six different models (Nicholls et al., 2002). The left and right pose of each model appeared side by side (counterbalanced) and was labelled A or B on a PowerPoint slide. The experimenter asked participants after each trial, Which picture do you think is more expressive, A or B? The second task involved asking participants to consider an imaginary setting such as, you have just passed all of your school exams with straight A grades. Think about how you feel and pose for the picture.
Results: Repeated measures logistic regression was used to see whether participants' cheek preferences could be predicted on the basis of participants' autism group status. Age and IQ were also considered as independent variables. Findings suggested that participants with autism use the left hemiface to judge emotional expressions, in line with typically developing populations. However when presenting their own poses, participants with autism fail to perform in line with their peers without autism, and do not show a left hemiface preference.
Conclusions: Participants with autism used their right hemisphere as productively as typically developing participants when observing and processing the emotional responses of others. These findings provide support for the hemisphere hypothesis (Burt & Perrett, 1997), which suggests that the right hemisphere is central for the creation and examination of emotional expression. Although this study provides evidence for individuals with autism perceiving emotional expressions in a similar way to those without autism, results indicate that they offer their left hemiface less frequently than typically developing peers. This suggests they are less able to display their own facial expressions of emotion in a typical fashion and this could lead to difficulties in effectively communicating in social interactions.